Michigan’s surveillance, prevention and response activities regarding West Nile virus (WNV) are a partnership involving the Michigan Departments of Agriculture (MDA), Community Health (MDCH), Environmental Quality (DEQ), and Natural Resources (DNR), local health departments and Michigan State University (MSU). This cooperative relationship dates back to before WNV was detected in Michigan and continues with the disease established in both humans and animals.

Michigan first experienced WNV activity in 2001, when 65 positive birds were identified in 10 counties in the Lower Peninsula. No human or equine cases were detected in 2001. In 2002, Michigan, along with other states, saw a dramatic increase in WNV activity in birds, equines, and humans. Michigan suffered the second highest number of WNV human cases in the nation with 644 laboratory positive cases detected by the MDCH Bureau of Laboratories. Fifty-one of these cases were fatal. In addition, there were 341 equine cases of WNV identified, and WNV positive birds were identified in 73 of 83 Michigan counties.

While no one can definitively predict how intense it will be, Michigan will again experience WNV activity in 2003. To prepare for this activity, Michigan’s West Nile Virus Response Team has proposed several initiatives to protect the citizens of Michigan and minimize transmission. Michigan’s approach will focus on communication, education, outreach activities, surveillance, personal protection and mosquito control recommendations.

Bird Disease Surveillance: Early experience with the virus in New York demonstrated that crows and blue jays are more sensitive to the virus than other birds, and more likely to die as a result of infection. Monitoring death amongst these birds can be an early indicator of virus activity. In 2001, a toll-free hotline, 888-668-0869, was established for citizens to report dead crows, and information was collected as to the location and condition of these birds, and appropriate birds were collected for testing. This system was continued in 2002.

For 2003, a system for web-based reporting of dead birds has been developed at www.michigan.gov/westnilevirus. This will allow for rapid reporting of dead bird sightings and provide a means of collecting appropriate birds for WNV testing. Individuals who do not have access to the Internet can report dead bird sightings through their local health departments. In order to provide community-based information about WNV activity in birds, testing will be conducted by zip code. When WNV is detected in a zip code, testing of birds will stop in that area, however dead bird sightings should continue to be reported online. Calculations of the number of dead birds per square mile in a county can be used to estimate the level of risk for human infection in that area. Communities can use this information to target intervention and prevention strategies to areas where WNV activity has been detected. In 2003 the toll-free hotline will be used for general, recorded WNV information.

Human Disease Surveillance: West Nile Virus is transmitted to humans primarily through the bite of a mosquito. Most people (80%) who are bitten by an infected mosquito do not get sick. For those who do become ill, they suffer with flu-like symptoms of fever, headache, body aches, fatigue, and on occasion, swollen lymph nodes and a rash. Approximately one in 150 people who are bitten by an infected mosquito develop a more serious form of the illness, including meningitis and encephalitis. The elderly and immuno-compromised are more susceptible to the more serious forms of illness, and possible death from WNV infection. Although they are quite rare, additional means of WNV transmission were documented in 2002 in organ transplantation, blood transfusion, breast-milk, transplacental, and occupational exposure in laboratory personnel conducting autopsies on birds.

Michigan will continue its laboratory testing for human cases of WNV illness. This strategy involves working with health care providers to alert them to the signs and symptoms of serious WNV disease and to ensure proper collection and handling of specimens. This involves regular communication with the Michigan Infectious Disease society, clinical laboratories and other health care organizations such as the Michigan State Medical Society, the Michigan Osteopathic Association. Last year, this aggressive outreach led to the testing of more than 2900 human specimens for WNV at MDCH.

Michigan will also take steps to monitor any adverse health complaints from ground and/or aerial applications of pesticides to control mosquito populations through:

• An existing hotline, 1-800-MI-TOXIC, for health care providers and the general public to call with concerns about potential adverse health effects from pesticides.

• Surveillance to monitor adverse health effects of spraying. This will include case identification, data collection and case follow-up. Results of the surveillance will be provided to affected communities and the MDA to ensure that spraying is conducted in compliance with the law and accepted practices protective of human health.

Horse Surveillance: The MDA Animal Industry Division maintains an active surveillance and communication system with private veterinarians in Michigan for detection of equine WNV cases. Equine veterinarians are contacted by telephone regularly to provide updates and to discuss potential cases.

Testing for WNV infection in live equine is done at the MSU Diagnostic Center for Population and Animal Health (DCPAH) on samples submitted directly from veterinarians. Horses and other equine with acute neurological signs that die or are euthanized are tested for WNV, and other diseases. MDA provides for transportation and testing costs.

A licensed equine WNV vaccine is available. MDA encourages vaccination of all horses, in consultation with private veterinary practitioners, as the most effective protection against infection, and promotes other measures horse/equine owners can take to reduce risk of mosquito exposure, including: decreasing mosquito breeding by draining puddles or repairing eave troughs, gutters and clearing any containers, tarps or rubbish that may hold pools of water; draining water tanks, troughs or buckets at least weekly or more often; using approved insect repellants to protect horses; placing horses in stables, stalls or barns under fans during the prime mosquito exposure hours.

Other Domestic Animal Surveillance: Other domestic animals may be tested as part of a general diagnostic laboratory evaluation. While WNV is not routinely considered as cause of disease or death in dogs and cats, reports of canine WNV infection and illness during the 2002 season raised concerns. In response, DCPAH may introduce and offer canine testing for the 2003 season.

Routine domestic animal test specimens will not be forwarded to the National Veterinary Services Laboratory (NVSL) as Michigan labs (DCPAH and MDCH) have full testing capability. Occasional NVSL testing may be requested on controversial specimens.

Mosquito Surveillance: Agencies agree that the best surveillance indicator of WNV activity is dead birds, particularly crows and blue jays. However mosquito surveillance can be a tool to help determine the potential for WNV disease transmission. Mosquito surveillance information such as species identification, mosquito densities, and possible breeding source locations are part of a comprehensive abatement program. MDA will again provide mosquito identification training to local health officials in 2003. MDA, MSU and local health departments can assist communities with mosquito species identification and trapping activities to assist in local decision making.

WNV is spread to humans almost exclusively through the bite of an infected mosquito. In 2003, we will continue to focus on educating the public on the many ways to reduce the risk of becoming infected by minimizing exposure to mosquitoes. The CDC has made Public Service Announcements on WNV available that can be incorporated into our television and radio broadcast schedules. Messages include:

• Applying insect repellent that contains the active ingredient DEET to exposed skin or clothing, always following the manufacturer’s direction for use on the label.
• Avoiding applying repellent to children under 2 years of age, and to the hands of older children because repellents may be transferred to the eyes or mouth potentially causing irritation or adverse health effects.
• Maintaining window and door screening to help keep mosquitoes out of buildings.
• Draining puddles in the yard. Empty water from mosquito breeding sites such as buckets, barrels, cans or similar sites in which mosquitoes can lay eggs.
• Avoiding being outdoors when mosquitoes are most active (dusk and dawn) and wearing light colored long-sleeved shirts and long pants when you have to be outdoors.

The state is recommending that local communities institute a mosquito abatement program at a level commensurate with risk, which emphasizes public education and source reduction.

Source Reduction: Each community at risk of WNV should encourage reduction of mosquito breeding sites, which will have a direct impact on the number of mosquito larvae. Mosquitoes that transmit WNV mature in stagnant water sites located throughout communities (drains, tires, discarded containers, etc). High priority should be given to early elimination of breeding sites through source reduction.

Communities, in cooperation with local health departments, should conduct public outreach and education to involve residents in source reduction efforts. While some activities may be as simple as emptying bird bath water frequently, other activities such as grading to reduce standing water or reducing foliage around standing water to increase surface turbidity are more complex and may require state and/or federal permits. Urban areas and "container" habitats should be targeted for the source reduction of mosquitoes rather than wetland areas and other waters of the state. The filling or draining of ponds and wetlands would not be helpful since the most common mosquito carrier of the virus is associated with urban rather than natural environments. State and/or federal permits may be needed to drain or fill flood plains or waters of the state, including wetlands such as cattail marshes, swamps and low lying areas of exposed Great Lakes bottomlands.

Communities may also want to identify local experts for mosquito surveillance or water management efforts, sharing this information with the public and managers of green spaces (golf courses, parks and recreation, department of public works, etc).

Reducing Mosquito Populations: In addition to source reduction, habitat modification, or the use of other intervention methods (other biological control organisms), the application of larvicides is recommended in certain situations to reduce the number of mosquito larva. Any application of a pesticide must occur only according to pesticide label use directions. Larvicides control the immature form of mosquitoes before they become adult vectors for WNV. Communities should identify, monitor and treat storm drains as necessary to reduce larval and adult mosquito populations in urban areas. The MDEQ must approve any application of pesticides to surface waters of the state and to wastewater treatment facilities, including but not limited to, storm water catch basins, treatment lagoons, and retention basins.

Targeted Spraying: When the risk of disease transmission to humans is present, targeted pesticide spraying, as part of a comprehensive, integrated pest management approach is an effective method for reducing the population of WNV-infected adult mosquitoes. Any local decision to use pesticides to control adult mosquitoes should be made using all available surveillance information and include measures such as source reduction and larvae control that result in focused efforts that produce desired, quantifiable results.

Spraying programs are regulated by MDA and require pre-notification and communication with the public when treatment for adult mosquitoes is planned. An informed public will better understand the measures being taken and will be able to take precautions to limit exposure to applications. Residents within a treatment area may request exclusion or pre-notification, as required by state regulations.

The application of pesticides must occur according to label use directions and requires applicators to be certified by MDA. Businesses that perform these services for hire must also be licensed with MDA. Communities considering the application of pesticides are advised to contact regional MDA offices for further information. Communities are advised that direct or incidental application of adulticides to surface waters is prohibited either by the pesticide use label or by state regulation.

Mosquito Control on MDNR Wildlife Division Administered Lands: MDNR’s Wildlife Division manages over 400,000 acres of state game and wildlife areas. These public hunting lands are managed for wildlife and are not in the immediate vicinity of human population centers. Mosquito control on DNR administered lands will be allowed when mosquitoes in specific areas are shown to be a direct threat to human health safety. Any mosquito control efforts on DNR-administered lands must be done consistent with all federal and state guidelines and requirements, as determined by the DNR Wildlife Management Supervisor in concert and with advice from local and state public health officials.

Mosquito Control on MDEQ Conservation Easement Areas: The DEQ’s Geological and Land Management Division (GLMD) currently holds over 1000 conservation easements and receives approximately 200 easements annually, generally in fulfillment of permit conditions. These lands may be in the vicinity of human population centers. Easements held by the DEQ do not allow for the spraying of pesticides, application of larvicides or any other kind of treatment for mosquitoes. However, in view of concern to WNV, the DEQ GLMD field staff will consider requests for mosquito control efforts on a case-by-case basis on select easements, commensurate with risk and verification by state public health officials. Mosquito control efforts must be consistent with federal, state and local guidelines and requirements.

Press Releases: A press release outlining Michigan’s strategy on WNV will be issued by Governor Granholm’s office. The release focuses on the wide range of efforts taking place to detect WNV and protect the residents of Michigan from the serious affects of the virus. This release will serve as a communications tool to be used by our state and local partners in educating citizens on the precautions they should take to minimize exposure to mosquitoes and components of the state’s 2003 season plan.

Internet: The state will launch a comprehensive website, www.michigan.gov/westnilevirus, to focus on all WNV-related areas. This inter-agency project involves MDA, MDCH, MDEQ, MNDR, Department of Information Technology, e-Michigan and MSU. The look and structure of the website will be similar to e-Michigan and will be maintained by the respective agencies.

We will rely on this site to disseminate updated information on the number of birds, horses, mosquitoes and other animals found with WNV, as well as human cases.

The site will be announced via the Governor’s press release and will also serve as the method for citizens to report dead birds to assist in on-going surveillance activities. In the past, citizens called a toll-free number to report dead bird sightings, which required much staff time and resources. By moving to on-line reporting, we can more effectively and accurately conduct surveillance. When a sighting is submitted via the website, the citizen will receive follow-up information according to whether or not the bird should be submitted for testing to local health authorities.

2003 Conference: A state-sponsored conference on WNV control has been planned for Wednesday, April 23, 2003, at the Holiday Inn South, Lansing. Conference information will be targeted to healthcare providers, veterinarians and local municipal authorities. Topics will include Human Disease Surveillance, Animal and Bird Surveillance, and Mosquito Prevention and Control. The agencies involved in planning and information are: MDA, MDCH, DEQ, DNR and MSU.

Hotline: For 2003, the toll free WNV hotline (1-888-668-0869) will provide updated general, recorded information to callers. Individuals who call the hotline will be directed to the state website on WNV for more detailed information.

Educational Materials: Written materials providing information about West Nile Virus, its symptoms and measures that individuals can take to reduce their risk of exposure to the virus will be available around the state in many locations, including local health departments.